The scuba clone idea is just perfect. In the end you should go with an oxygen tank-backpack, couple of hoses to your helmet, and go with hydrodynamic shapes, like avoid squared frames and go with soft curves, and some fins here and there (gauntlets, helmet, back, back of the shins).
Beside armor design, i think you should ask yourself of you want to go in the scuba assaultman (woman), or the aquatic beast tamer/hunter.
In the first case i'd go with grey colors (warships and submarines are gray) and think about tactical equipment, modern materials, maybe an harpoon rifle or similar, fins hanging on your belt.
If you go with the beast tamer or similar way, you can go with more common tools, use canvas, or burlap, blue and green colors, fishing trophies. Maybe a net or a spear/trident.
It really depends on where you are heading.